Railway traffic controlling apparatus



July 2, 1940. w. P. PLACE 2,206,579

RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Aug. 3, 1938 2 Sheets-$heet 1 IFD 180a M2 WL X12 XL m4 180k I {I2 To Sclqzzal WS'.

\ IN ENTOR RPlaoe. Fig. 2. BY

H15 ATTORNEY July 2, 1940. PLACE 2,206,579

RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed Aug. 3, 1938 2 Sheets-Sheet 2 INVENTOR v [alf- HIIS' ATTORNEY Patented July 2, 1940 OFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Willard P. Place, Wilkinsburg, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Original application August 3, 1938, Serial No.

Divided and this application October 7, 1939, Serial No. 298,435

Claims.

My invention relates to railway traffic controlling apparatus, and particularly to apparatus for railway cab signal systems.

The present application is a division of my copending application Serial No. 222,883, filed August 1938, for Signal systems.

I shall describe several forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims. I

Railway cab signal systems using track circuits supplied with coded alternating current are in general use. Alternating current of a convenient frequency such as 100 cycles per second is periodically interrupted at different code rates or frequencies according to different trafiic conditions, the code rates of 180, 120 and 75 being generally used to reflect clear, approach restricting and approach trafiic conditions, respectively. Energy is received by a train carried circuit coupled with the track circuit and such energy is used to govern a cab signal through decoding apparatus selectively responsive to these different code rates or frequencies. Such decoding apparatus has been standardized in construction for the present day cab signal systems.

Railway cab signal systems using track circuits supplied with coded direct current have been proposed. Time spaced impulses of direct current of a preselected polarity are supplied to a track circuit at different code rates according to different traflic conditions in advance of the track circuit, and the code rates of 180, 120 and '75 may be employed the same as in systems using coded alternating current. The individual impulses of direct current are preferably of relatively high peak voltage and of short duration. The high peak voltage serves as an aid to the shunting sensitivity of the track circuit and the short duration serves to limit the energy output from the current source, which is ordinarily a battery, to a low energy level. Energy is received on the train by a train carried circuit coupled with the track circuit and such energy is used to govern a cab signal through decoding apparatus which preferably is of the standard construction.

A railway having certain divisions already equipped with track circuits using coded alternating current may find it desirable to equip other divisions with track circuits using coded direct current and to operate locomotives provided with cab signals over either division. That is to say, a railway may wish to use a locomotive equipped with cab signals either with a territory having coded alternating current track circuits or with territory having coded direct current track circuits, the cab signals being controlled by both forms of track circuits. It becomes necessary to equip such locomotive with train carried receiving apparatus that controls a cab signal in response to energy received from either a track circuit supplied with coded alternating current or from a track circuit supplied with coded direct current.

Accordingly, a feature of my present invention .is the provision of novel and improved receiving apparatus for cab signal systems which apparatus can be used either with coded alternating current or with coded direct current. Again, a feature of my invention is the provision of receiving apparatus of the type here involved having automatic switching means for selectively rendering active one or the other of two receiving channels operating in parallel, one of such receiving channels being selectively responsive to code impulses of direct current and the other of such receiving channels being selectively responsive to coded alternating current. Other features and advantages of my invention will appear as the specificationv progresses.

In the accompanying drawings, Fig. 1 is a diagrammatic View showing one form of track- Way apparatus embodying my invention when applied to a four indication signaling system for railways. Figs. 2, 3 and 4 are diagrammatic views showing three different forms of train carried apparatus each embodying my invention when applied to a four indication cab signaling system.

In each of the several views similar parts are designated by similar reference characters.

Referring to Fig. 1, the track rails Id and lb of a stretch of railway track are formed into consecutive insulated track sections of which only one full section W-X and the adjoining ends of the two adjacent sections are shown for the sake of simplicity. Each track section is provided with a track circuit comprising the track rails, means for supplying code impulses of direct current connected across the rails at the exit end of the section, and a code responsive relay means connected across the rails at the entrance end of the section. Thus the source of current impulses for the track circuit for the section WX and the code responsive relay means for the track circuit for the section to the left as viewed in Fig. 1, that is, the track circuit next in advance of section W-X, are located adjacent the junction W of these two track sections. The means for supplying such code impulses of direct current to a track circuit is governed by the code responsive relay means for the track circuit for the section in advance according to different trafiic conditions in advance.

The source of code impulses of direct current for the track circuit for the section W-X comprises a battery 2, a track transformer Tl and a code transmitter 0T2. A portion of a winding 4 of transformer TI is connected across the rails former T8 adjacent the exit end W of section WX. The full winding 4 of transformer TI is connected with battery 2 over contacts of the code transmitter CT2 in accordance with traffic conditions in advance. The code transmitter GT2 is preferably of the frequency code type, several of such types being well known to the art. operating winding of code transmitter CTZ is connected with a convenient source of current and is continuously activev to operate three code contact members 15b, I?) and I801), the arrangement being such that the code contact member 75b is operated to close contact I5aI5b at the rate of say 75 times per minute, code contact member I2Ilb is operated to close contact I2Ila,I20b at the rate of 120 times per minute and the code contact member I801) is operated to close contact I80w-I80b at the rate of 180 times per minute.

At such time as a relay WA of the code responsive relay means to be later referred to for the track circuit of the section next in advance of section WX is picked up closing front contact I43, or when relay WA is released closing back contact I44 and a second relay WR of the code responsive relay means is picked up closing front contact I45, the battery 2 is connected across the winding 4 of transformer TI over contact I80a-I8Ilb of the code transmitter GT2 and direct current impulses of the code rate or frequency of 180 per minute are supplied to the track circuit for section W- -X, the polarity of the code impulses of current being all the same, for example, they may be all of positive polarity. When both relays WA and WE are released closing back contacts I44 and I46, respectively, and a third relay WL of the code responsive relay means is picked up closing front contact I41, the battery 2 is connected across winding 4 over contact I20a-I20b of the code transmitter GT2 and direct current impulses of the code rate or frequency of 120 impulses per minute are supplied to the track circuit of section WX, the impulses being all of positive polarity. Again, when relays WA, WR and WL are all released closing back contacts I44, I46 and I48, respectively, battery 2 is connected across winding 4 over contact I5a--'I5b of the code transmitter andthe track circuit for section WX is supplied with impulses of direct current at the code rate or frequency of 75 impulses per minute, the impulses being all of positive polarity.

The code responsive relay means for the track circuit of section WX includes a code following relay XTRI connected across the rails at the entrance end of the section. Code following relay XTRI is effectively energized and picked up by each impulse of direct current supplied to the track circuit and hence relay XTRI operates its contact member I49 at the code rate or frequency of the impulses supplied to the track circuit. Operation of the code contact member I49 causes direct current to be alternately supplied to the two portions of primary winding I50 of a transwith the result that electromotive force of a frequency corresponding to the rate at which contact member I49 isoperated is induced in the secondary winding I5I of that transformer and is applied to the input terminals of a frequency decoding unit 2WD. The specific structure of the frequency decoding unit m is immaterial, several of such decoding units being well known. Preferably the structure of the decoding unit XFD would be that of standard construction. It is deemed sufficient for this appli- The cation to say that the decoding unit XFD causes a relay XA connected with its output side to be energized and picked up only in response to current impulses corresponding to relay XTRI operated at the 180 code rate, causes a relay 2m connected with its output side to be energized and picked up only in response to current impulses corresponding to relay XTRI operated at the 120 code rate, and causes a relay XL connected with its output side to be energized and picked up in response to relay XTRI operated at either the 180, 120 or 75 code rate.

In like fashion a code following relay WTRI for the track circuit of the section next in advance of section WX governs through a transformer T9 a frequency decoding unit WFD for selectively energizing the relays WA, WR and WL in accordance with the code rate of the impulses of the track circuit current of that section.

It should be pointed out that the code rate of 180 impulses per minute for a track circuit represents clear traffic conditions, the code rate of 120 impulses per minute for the track circuit represents approach restricting traflic conditions, the code rate of 75 impulses per minute for the track circuit represents approach traffic conditions, and the absence of any of these code impulses represents stop or slow speed traffic conditions.

The relays WA, WR and WL govern the operating circuits for a wayside signal WS which governs traffic through the track section next in advance of section WX. These operating circuits for signal WS are shown conventionally only in Fig. l for the sake of simplicity, since they would be in accordance with standard practice and form no part of my present invention.

The relays XA, XR and XL for the track circuit of section WX govern the track circuit for the section next in the rear and the operating circuits for a wayside signal XS in the same manner as the relays WA, WR and WL control the track circuit of section WX and the operating circuits for signal WS.

It should be pointed out that the code impulses of direct current applied to the track circuits of section WX are of relatively short duration and relatively high peak voltage as explained fully in my copending application Serial No. 222,883.

The track circuit of each track section of the stretch of railway of which section WX forms a part would be provided with trackway apparatus the same as described for the track circuit of section WX.

Another stretch of the railway would be arranged into consecutive track sections each of which is provided with trackway apparatus operating to supply to the track circuits coded alternating current. The alternating current would preferably be periodically interrupted or codedat the code rate or frequency of 180, 120 and '75 impulses per minute according to clear, approach restricting and approach trafiic conditions in advance. Trackway apparatus operative to supply such coded alternating current is well known and in widespread use and may be that disclosed in the United States Letters Patent No. 1,773,515, granted August 19, 1930 to Charles C. Buchanan, for Railway traific controlling apparatus.

Referring to Fig. 2, the train carried apparatus includes an inductor or receiving circuit comprising two windings and 26 mounted on the train in inductive relation with the track rails la and lb, respectively. The connections of wind ings 25 and 26 are preferably such thatthe electromotive forces induced therein by current flowing in opposite directions in the rails Ia and lb at any given instant add their effects.

The train carried apparatus of Fig. 2 is pro vided also with two receiving channels one effectively influenced by recurrent impulses of direct current and the other effectively influenced by coded alternating current. If the train on which the apparatus of Fig. 2 is mounted is operating over territory where the track circuits are supplied with coded direct current impulses such as provided by the trackway apparatus of 1, a receiving channel including a controlled ionization type of electron tube is responsive thereto. ing over territory where the track circuits are supplied with coded alternating current of 100 cycles per second such as is widely used in present day cab signaling systems and such as provided by trackway apparatus shown in the aforementioned United States Letters Patent' No. 1,773,515, a receiving channel including a high vacuum amplifying electron tube is responsive thereto.

In Fig. 2, the receiving channel responsive to direct current impulses includes an input transformer TI2, a controlled ionization tube G3 and a master code following relay MRI. The receiving channel responsive to coded alternating current includes an input transformer TIS, a high vacuum pentode tube ZELE and a master code following relay MR. The inductor windings 25 and 26 are connected with the primary windings H2 and N3 of the transformers TH! and TH, respectively, in multiple. Hence energy received from the track circuit is applied to the two receiving channels in parallel,

Referring to the receiving channel responsive to impulses of direct current, the controlled ionization tube G3 is of the indirect heater type, the

two principal electrodes being anode I6 3 and cathode I65, and its control element being a grid N56. The grid circuit for tube G3 is connected with a secondary winding I15 of the input transformer TIZ as will be apparent by an inspection of Fig. 2. A generator 84 of a'motOr generator MG serves as the source of electromative force for the anode circuit of tube G3, the motor 85 of the motor generator MG being supplied with current from any convenient source such as a headlight generator (not shown) whose terminals are B32 and N32. The generator 84 whose terminals are designated B306 and N390 would, for example, supply a voltage 'of say 300 volts.

The anode circuit for tube G3 includes terminal B304} of generator 84, a resistor 32, top winding of code following master relay MRI, anode I64, tube space to cathode I and terminal N369 of the generator. A condenser CI and an inductor LI are connected with this anode circuit to provide the tube G3 with an oscillatory circuit, this oscillatory circuit extending from condenser Cl over inductor Ll, top winding of relay MRI, the anode-cathode space of tube G3 and back to condenser CI. Normally the voltage applied by generator 34 is ineffective to render the tube G3 conducting and hence the condenser Cl is normally charged at substantially the voltage of generator 85. The relay MRI when operated causes through its contact member 559 direct current to be alternately supplied to the two portions of winding I68 of a transformer When the train is operat TI I over a circuit to be later traced, with the result that electromotive forces are induced in secondary winding I61 of transformer TH and cur rent impulses of a rate corresponding to the rate at which relay MRI is operated are supplied to the input terminals of a frequency decoding unit TFD. A resistor I9! is preferably connected across the supplycircuit ahead of the contact -rnember I69 to allow a substantially uniform flow of direct current through the winding I68 when relay MRI is not operated. A further pur: pose of resistor I91 will appear hereinafter.

The frequency decoding unit TFD would preferably be of standard construction and relays TA, TR and TL connected withthe output side of the decoding unit TF'D are selectively energized according to the code rate of the impulses of current supplied to the decoding unit, the arran ement being that relay TA is energized and picked up when and only when the -relay MRI is operated at the code rate of 180, relay TR'is energized and picked up when and only when re-' lay MRI is operated at the code rate of 120 and relay FL is energized when relay MRI is operated at either the'lSO, 120 or code rate. The relays TA, TR and TL are used to govern the operating circuits for a cab signal CS1 as is obvi ous from Fig. 2. v

Referring now to the receiving channel responsive to coded alternating current and which T13 and condensers I14 and I84 form a filter interposed between windings 25 and Z6 and the control element of tube 25MB and which filter is tuned sharply to pass only the frequency of the alternating current, that is, the filter is tuned 'to resonance at the frequency of cycles per second.

The electron tube ZfiLB'is of the low voltage type and its plate circuit is supplied from the B32-N32 source of current, plate ll"! of tube 25H) being connected with terminal B32 through primary winding I78 of a transformer TM, and cathode N9 of the tube being connected with terminal N32 through a biasing resistor I98. The secondary winding IBI of transformer T14 is connected with the winding of code following relay MR. Code following relay MR is of the usual code following type and is provided with two contact members I32 and 83 which remain in the position to which they were last moved when the relay is deenergized. Relay MR controls the supply of direct current to winding H38 of transformer TM in a manner to shortly appear and.

hence when operated causes impulses of current to be supplied to the input side of decoding unit TFD which impulses are of a rate corresponding to the rate at which relay MR is operated. It follows that alternating current of the code rates of 180, and.'l5 when applied to the receiving channel including tube 25L6 is amplified and decoded to control relays TA, TR and TL and in turn to control cab signal CS! in accordance with the code rate.

Assuming the train on which the apparatus of Fig. 2 is mounted is moving over the track section. VX of Fig. 1 under clear traffic conditions so that direct current impulses of code rate are supplied to the track circuit, corresponding electromotive forces are induced in the windings 25 and 26 and are applied to the two receiving channels in parallel. Since the wave form of the electromotive force induced in windings 25 and 26 in response to the direct current impulses contain little if any alternating current'energy of 100 cycles, the filter comprising the transformer TI3 and condensers I14 and I84 substantially blocks all such energy from tube 25L6 and the receiving channel including tube 25L6 is not affected by such current impulses.

The windings of transformer TIZ are so connected that the first half cycle of the electromotive force induced in the secondary'winding I15 of transformer TI2 in response to a track circuit impulse of direct current of positive polarity causes the grid I'66 of tube G3 to be positive in potential with respect to the cathode I65 and tube G3 is ionized and becomes conductive. Current flows from condenser CI through inductor LI, top winding of relay MRI, anodecathode space of tube G3, and back to condenser CI. Current also flows from generator 84 through the associated anode circuit including resistor 32 and the top winding of relay MRI as wellas the anode-cathode space of tube G3. Because of the oscillatory nature of the discharge from the condenser CI, the current through tube G3 falls after a first surge to a relatively low value and the tube G3 deionizes and becomes nonconducting. The condenser CI is quickly recharged and the above described operation is repeated for each code impulse of direct current of the track circuit, and relay MRI is operated at the code rate of 180. It should be observed that the negative half cycle of the induced electromotive force does not affect ionization of tube G3.

Relay MRI when thus operated causes direct current to be alternately supplied to the two portions of primary winding I68 of transformer TII over a signaling or supply circuit which can be traced from terminal B over contact member I83 of relay MR in its right-hand position, primary winding I85 of a transformer TI5 to be referred to, left-hand portion of winding I68 of transformer TH and back contact of contact member I69 of relay MRI or right-hand portion of winding I68 and front contact of contact member I69, contact member I82 of relay MR in its right-hand position and to terminal 0. It follows that current impulses of a rate corresponding to the 180-code rate are supplied to 55 the decoding unit TFD and relay TA in turn is effectively energized and picked up to cause signal CSI to display a clear indication.

Since the impulses passed by tube G3 are relatively short and since it is desirable that code 9 impulses supplied to the decoding unit TFD have nearly equal on and off periods, the relay MRI is provided with a lower winding which is connected with a reactor L3 over front contact I96. When relay MRI is released (ofi position) reactor L3 is supplied with current from the source B32N32 over back contact I95 and reactor L3 stores up magnetic energy, the amount of energy depending within limits upon the length of time reactor L3 is supplied with 9 current. When relay MRI is picked up (on a position) the reactor L3 is connected withthe lower winding of relay MRI and disconnected from the current source. This causes current to flow in the lower winding of relay MRI due to the decay of the magnetic energy stored in reactor L3 and relay MRI is maintained energized for an interval subsequent to the termination of the impulse of current flowing in the top winding ofthat relay due to the action of tube G3. Thus the current impulses supplied to decoding unit TFD due to the operation of relay MRI have substantially equal on and off periods.

Operation of the apparatus in response to direct current impulses supplied to the track circuit of section WX of the 120 or 75 code rate in accordance with different traffic conditions causes relay MRI to be operated at a corresponding code rate and relays TR and TL to be picked up at the 120 code rate and relay TL only picked up at the '75 code rate so that cab signal CSI is caused to display an approach restricting indication or an approach indication according to the traflic condition.

It should be noted that the transformer TI5 is-so designed and proportioned that when the relay MRI is operated in the manner explained above, the electromotive forces induced in the secondary winding I86 when rectified by a full wave rectifier I81 are not effective to energize a relay R6 whose winding is connected across.

the output terminals of rectifier I81 sufficiently to pick up that relay. Furthermore, the resistor I91 which allows a substantially uniform -amount of direct current to flow when relay MRI is operated aids in assuring that not sufficient energy is supplied to relay R6 to pick up that relay.

Assuming the train on which the apparatus of Fig. 2 is mounted is operating over a track circuit to which coded alternating current is supplied by trackway apparatus of the aforementioned United States Letters Patent No. 1,773,515 at the code rate of 180, 120 or '75 according to different traffic conditions, each on period of the alternating current induces an,

electromotive force in the windings 25 and 26 operated 'causes current from the source B--C to be reversibly supplied to the left-hand portion of winding I68 of transformer TII over the previously traced supply circuit with the result that electromotive forces are induced in the secondary winding I61 of transformer TH and impulses of current of a corresponding rate are applied to the decoding unit TFD so that relays TA, TR and TL are selectively controlled according to the code rate at which relay MR is operated and signal CSI displays an indication corresponding to the code rate of the alternating current supplied to the track circuit.

When relay MR is operated, the direct current flowing in primary winding I85 of transformer TI 5 is periodically reversed and the electromotive force induced in secondary winding I86 of that transformer when rectified by rectifier I81 is of suflicient magnitude to effectively energize relay R6 to pick up that relay, relay R6 being retained picked up from one impulse of the track circuit current to the next due to its slow releasing characteristic. Relay R6 in picking up opens its back contact I88 and removes current from motor 85 of the motor generator MG so that generator 84 no longer supplies current to the anode circuit of tube G3, with the result that the receiving channel including tube G3 is desensitized. That is, relay R6 is operated by the receiving channel responsive to coded alternating current and automatically switches the receiving channel responsive to direct current impulses to an inactive condition.

In Fig. 3, the train carried apparatus comprises two receiving channels the same as in Fig. 2. In Fig. 3, the controlled ionization electron tube G3 of the receiving channel responsive to recurrent impulses of direct current is preceded by a stage of amplification including a high vacuum electron tube 6Q! of the indirect heater type and having two diode plates I89 and I90. The grid circuit of tube G3 is coupled with the plate circuit of the preceding amplifier'tube GQl by a circuit including resistors I6! and I 62 and a condenser I63. A resistor lEiI is interposed in the grid circuit of tube G3 between the resistor 2 and the terminal N32. The grid circuit for tube fiQl is connected directly with the inductor windings 25 and 26, a resistor I92 being interposed in the circuit adjacent the terminal N32 as is apparent from Fig. 3. The resistors m2 and I9! provide desirable normal grid bias voltages for tubes G3 and'fiQl, respectively.

The receiving channel of Fig. 3 responsive to coded alternating current includes transformer TI3, tube ZSLG and master relay MR the same as in Fig. 2, the windings of transformer T63 and condensers i IQ and I84 forming a filter interposed between the grid of tube 25116 and the inductor windings 25 and 26.

The master relays lVlR and N135 control current impulses supplied to the frequency decoding unit TFD by controlling the supply of direct current to the primary winding I58 of transformer III in the same manner as in Fig. 2 except in Fig. 3 the transformer TI5, rectifier I8'I, relay R6 and resist-or I9? are omitted.

In Fig. 3, the means for desensitizing the receiving channel including tube 25H; so that it is not responsive to direct current impulses consists of the filter including condensers I'M and I84 and transformer TI3 the same as in Fig. 2. In Fig. 3, the means for automatically desensitizing the receiving channel including tube G3 when coded alternating current is picked up from the track circuits includes two condensers I93 and I94. Condenser I93 is connected between a point P in the supply circuit for transformer TI I and the resistor I9I of the grid circuit of tube G3, and condenser I94 is connected between a point Q in the supply circuit for transformer TII and the resistor I92 of the grid circuit of tube BQI. Also one side of condenser I93 is connected with the diode plate I of tube IiQl over wire I99 and one side of condenser H4 is connected with diode plate I89 over wireZIiQ. Point P is located in the supply circuit between the contact member I82 of relay MR and contact member I69 of relay MRI, and point P is located in the supply circuit between the contact member 283 of relay MR and the mid terminal of winding I68 of transformer TI I.

When the train on which the apparatus of Fig. 3 is mounted operates over track circuits supplied with code impulses of direct current of different code rates as provided by the trackway apparatus of Fig. l, the receiving channel including tube G3 and relay lVLRI is responsive and operates in the same manner as described in detail in Fig. 2 except that the electromotive forces inating, the voltage appearing between points P and Q is essentially a direct current voltage waether master relay MRI is operating or not.

When relay MR is operating in response to code impulses-of alternating current, the current supplied to winding i88 is periodically reversed and surges of alternating current voltages appear be-.

tween points P and Q whenever relay MR operates to interrupt the circuit, The alternating voltages appearing between points P and Q are supplied through condensers I93 and i9 1 to the diode plates I89 and I9!) of tube 6Q! Where such voltages are rectified and applied as unidirectional voltages across resistors I9I and I92. Such rectified unidirectional voltages create voltages which are added to the normal negative bias voltages of tubes 6Q! and G3. The parts are so proportioned that the grid bias voltages applied to tubes 6Q! and G3 are correct only when no rectified current is applied to resistors IQI and I92.

The voltages created by the rectified current flowing in these resistors when added to the normal bias voltages causes tubes BQ'I and G3 to be so highly negative that they no longer function.

Consequently, when the train is operated over territory in which the track circuits are supplied with coded alternating current, the receiving channel normally responsive to direct current impulses is desensitized, and when the train is operating over territory using track circuits in which impulses of direct current are supplied, the receiving channel normally responsive to alternating current is unaffected due tothe tuning of the filter included in that receiving channel.

In Fig. 4, the train carried apparatus is the same as in Fig. 3 except for the means used to desensitize the tubes 6Q! and G3. In Fig. 4, the diode plates I89 and I90 of tube 6Q! are connected in a full wave rectifier circuit made up of condensers I93 and I94 and an additional condenser ZEII, together with resistors 2%, 233 and 204. Alternating surges of voltages appearing at points P and Q when master relay MR is operating are rectified by the diode plates I89 and I90 and are efiective to charge the condenser 2M. The voltage across condenser 2M when thus charged adds to the normal bias voltages of tubes 6Q! and G3, and these tubes are provided with a bias of such negative potential that they can no longer operate.

It is clear, therefore, that when a train on which the apparatus of Fig. 4 is mounted operates over territory using track circuits supplied with coded alternating current, the receiving channel including tube 25116 and relay MB is responsive to control the cab signal CSI. When thetrain operates over territory using'track circuits supplied with coded direct current, the receiving channel including tube. G3 and relay MRI is responsive to control the cab signal CSI, the operation being substantially the same as described in connection with the apparatus of Fig. 2.

It is to be understood, of course, that the train carried apparatus of any of the several forms of apparatus embodying my invention can include circuits for controlling the air brake and power equipment according to any of the well-known arrangements, if desired.

Although I have herein shown and described only certain forms of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. Railway traffic controlling apparatus for use either with a first territory provided with track circuits supplied with alternating current of a given frequency coded at different code rates according to different traific conditions or with a second territory provided with track circuits supplied with direct current coded at said different code rates according to said different traffic conditions comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, a first train carried receiving channel including a first code following relay normally effective to operate said first relay when energy is periodically applied to the input terminals of that channel, a second train carried receiving channel including a second code following relay normally effective to operate said second relay when energy is periodically applied to the input terminals of that channel, means including a filter tuned to resonance at said given frequency of said alternating current to connect said receiving circuit with the input terminals of said first channel to operate said first relay only when the train traverses said first territory, means to connect said receiving circuit with the input terminals of said second channel, means including a contact of said first relay to desensitize said second channel when said first relay is operated to permit operation of said second relay only when said train traverses said second territory, a'decoding unit selectively responsive 'to current impulses corresponding to said different code rates, circuit means including a contact of each of said relays to supply such current impulses to said decoding unit when either of said relays is operated, and a signal having a different indication for each of said different 'trafiic conditions controlled by said decoding unit.

2. Railway traffic controlling apparatus for :use either with a first territory provided with track circuits supplied with alternating current of a given frequency coded at different code rates according to different traific conditions or with a second territory provided with track circuits supplied with direct current coded at said different code rates according to said different traffic conditions comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, a first and a second train carried receiving channel the input terminals of which are connected in parallel to 'said receiving circuit; each of said receiving of said first channel to desensitize the tube' of said second channel'when the relay of the first channel is operated to permit operation of the relay of the second channel only when the train traverses said second territory, a decoding unit selectively responsive to current impulses corresponding to said different code rates, and circuit means including a contact of each of said relays to control said decoding unit.

3. Railway traffic controlling apparatus for use either with a first territory provided with track circuits supplied with alternating current of a given frequency coded at difierent code rates according to different traffic conditions or with a second territory provided with track circuits supplied with direct current coded at said different code rates according to said different traffic conditions comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, a first and a second train carried receiving channel; said first channel including a first electron tube, a first relay and a current source; said first tube having its control element connected with said receiving circuit and its anode and cathode connected with said current source through a winding of said first relay, said first channel normally effective to cause said first relay to be operated when energy is periodically applied to the control element of said first tube; said second receiving channel including a second electron tube, a second relay and a current source; said second tube having its control element connected with said receiving circuit and its anode and cathode connected with the associated current source through. a winding of said second relay, said second channel effective to cause said second relay to be operated when energy is periodically applied to the control element of said second tube, a filter tuned to resonance at said given frequency interposed in the connection of the receiving circuit with the control element of said first tube to operate said first relay when the train traverses said first territory, means including a contact of said first relay to desensitize said second tube when said first relay is operated to permit operation of said second relay only when the train traverses said second territory, a decoding unit selectively responsive to current impulses corresponding to said different code rates, and circuit means including a contact of each of said relays to control said decoding unit.

4. Railway trafiic controlling apparatus for use eitherwith a first territory provided with track circuits supplied with alternating current of a given frequency coded at different code rates according to different trafiic conditions or with a second territory provided with track circuits supplied with direct current coded at said different code rates according to said different traffic conditions comprising, a train, a receiving circuit mounted on the train for receiving energy'from such track circuits, a first and a second train carried receiving channel; said first receiving channel including a high vacuum electron tube, a first relay and a current source; said electron tube having a grid circuit coupled with said receiving circuit and an anode circuit including a winding of said relay and said current source, said first channel normally effective to operate said relay when alternating current is periodically supplied to said grid circuit; said second receiving channel including a controlled ionization electron tube, a second relay, a reactance device and a current source: said controlled ionization tube having a control element coupled with said receiving circuit and an anode circuit including a winding of said second relay and the associated current source, said reactance device connected with the anode and cathode of the controlled ionization tube to store energy in the device when the tube is nonconductive and give up such stored energy to deionize the tube when the tube is made conductive, said second channel normally effective to operate said second relay when energy of a preselected polarity is applied to the control element of said controlled ionization tube, a filter tuned to resonance at said given frequency interposed in the coupling between the grid of said high vacuum'tube and the receiving circuit to permit operation of said first relay only when the train traverses said first territory, means including a contact of said 7 first relay to desensitize said controlled ionization tube when said first relay is operated to permit operation of said second relay only when the train traverses said second territory, a decoding unit selectively responsive to current impulses corresponding to said different code rates, and circuit means including a contact of each of said relays to! control said decoding unit.

5. Railway trafiic controlling apparatus for use either with a first track circuit supplied at times with coded alternating current of a given frequency or with a second track circuit supplied at times with coded direct current of a given polarity comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, a first and a second train carried receiving apparatus; said first receiving apparatus including a first electron tube, a first relay and a current source; said first tube having its control element coupled with said receiving circuit and its anode and cathode connected with said current source through said first relay and said first aparatus arranged to cause operation of the first relay when an electromotive force is periodically applied to the control element of said first tube; said second receiving apparatus including a second electron tube, a

second relay and a current source; said second tube having its control element coupled with said receiving circuit and its anode and cathode connected with the associated current source through said second relay and said second apparatus arranged to cause operation of said second relay when an electromotive force of a selected polarity is periodically applied to the control element of said second tube, a filter tuned sharply to pass only alternating current of said given eluding a contact of each of said relays effectively controlled when either relay is operated.

6. Railway trafiic controlling apparatus for use either with a first track circuit supplied at times with coded alternating currentv of a given frequency or with a second track circuit supplied at times with coded direct current of a given polarity comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, a first and a second train carried receiving, apparatus; said first receiving apparatus including a high vacuum electron tube, a first relay and a current source; an anode circuit including said first relay and said current,

source for said tube, a grid circuit for said tube coupled with said receiving circuit to cause operation of'said first relay when energy is periodically applied to the grid from said receiving cir-- cult; said second receiving apparatus including a controlled ionization electron tube, a second relay, a condenser and a current source; an anode circuit including said second relay and said last mentioned current source for said controlled ionization tube normally ineffective to ionize the tube, a circuit including said condenser connected; with the anode and cathode of the controlled ionization tube to deionize the tube when the tube is conductive, a grid circuit for said con,- trolled ionization tube coupled with the receiving circuit to ionize that tube and operate said second relay when energy of said given polarity is received by said receiving circuit, a filter tuned to pass only current of said given frequency in-. terposed in the grid circuit of said high vacuum tube to operate said first receiving apparatus only when the train occupies said first track circuit, means including a contact of said first relay to desensitize said controlled ionization tube when said first relayis operated for operat.-- ing said second receiving apparatus only when the train occupies said second track circuit, and a signaling circuit including a contact of each of said relays effectively controlled when either relay is operated.

7. Railway traflic controlling apparatus for use either with a first track circuit supplied at times, with coded alternating current of a given frequency or with a second track circuit supplied at times with coded direct current of a given po-- larity comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, at first and a second train carried receiving apparatus; said first receiving apparatus including a high vacuum electron tube, a first relay and a current source; an anode circuit including said first relay and said current source for said tube, a grid circuit for said tube coupled with said receiving circuit to cause operation ofsaid first relay when energy is periodically applied to the grid from said receiving circuit; said second receiving apparatus includinga controlled ionization electron tube, a second relay, a condenser and a curent source; an anode circuit including said second relay and said last mentioned current source for said controlled ionization tube normally ineffective to ionize the tube, a circuit including said condenser connected with the anode and cathode of the controlled ionization tube to deionize the tube when: the tube is conductive, a grid circuit for said controlled ionization tube coupled With the receiving circuit to ionize that tube and operate said. second relay when energy of said given polarity is received: by said receiving circuit, a filter tuned to resonance at said given frequency interposed in the grid circuit of said high vacuum tube to cause operation of said first relay only when the train occupies said first track circuit, a signaling, circuit including a contact of each of said relays eiiectively controlled when either of said relays is operated, another relay controlled by said sig naling circuit and effectively energized only when said first relay is operated, and meansincluding a back contact of said other relay to remove the current source of the second receiving apparatus from the anode circuit of said. controlled ionizas.

tion tube to permit operation of said second relay only when the train occupies said second track circuit.

8. Railway trafiic controlling apparatus for use either with a first track circuit supplied at times with coded alternating current of a given frequency or with a second track circuit supplied at times with coded direct current of a given polarity comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, a first and a second train carried receiving apparatus; said first receiving apparatus including a high vacuum electron tube, a first relay and a current source; an anode ciri cuit including said first relay and said current source for said tube, a grid circuit for said tube coupled with said receiving circuit to cause operation of said first relay when energy is periodically applied to the grid from said receiving circuit; said second receiving apparatus including a controlled ionization electron tube, a second relay, a condenser and a current source; an anode circuit including said second relay and said last mentioned current source for said controlled ionization tube normally ineffective to ionize the tube, a circuit including said condenser connected with the anode and cathode of the controlled ionization tube to deionize the tube when the tube is conductive, a grid circuit for said controlled ionization tube coupled with the receiving circuit to ionize that tube and operate said second relay when energy of said given polarity is received by said receiving circuit, a filter tuned to resonance at said given frequency interposed in the grid circuit of said high vacuum tube to cause operation of said first relay only when the train occupies said first track circuit, a signaling circuit including a contact of each of said relays effectively controlled when either of said relays is operated, and biasing means including another condenser connected with the grid circuit of said controlled ionization tube and with said signaling circuit to create a negative grid bias for that tube when said first relay is operated whereby said second receiving apparatus is effective to operate said second relay only when the train occupies said second track circuit.

9. Railway trafiic controlling apparatus for use either with a first track circuit supplied at times with coded alternating current of a given frequency or with a second track circuit supplied at times with coded direct current of a given polarity comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, a first and a second train carried receiving apparatus; said first receiving apparatus including a high vacuum electron tube, a first relay and a current source; an anode circuit including said first relay and said current source for said tube, a grid circuit for said tube coupled with said receiving circuit to cause operation of said first relay when energy of said given frequency is periodically applied to said grid from said receiving circuit; said second receiving apparatus including a controlled ionization electron tube, a second relay, a condenser and a current source; an anode circuit including said second relay and said last mentioned current source for said controlled ionization tube normally ineffective to ionize the tube, a circuit including said condenser connected with the anode and cathode of the controlled ionization tube to deionize the tube when the tube is conductive, a grid circuit for said controlled ionization tube coupled with the receiving circuit to ionize that tube and operate said second relay when energy of said given polarity is received by said receiving circuit, a filter tuned to resonance at said given frequency interposed in the grid circuit of said high vacuum tube to cause operation of said first relay only when the train occupies said first track circuit, a signaling circuit including a source of direct current and a transformer, a first and a second contact of said second relay interposed in said signaling circuit to alternately supply current to two half portions of a winding of said transformer when that relay is operated, a first and a second contact of said first relay interposed in said signaling circuit to reversibly supply current to a selected half portion of said transformer winding when that relay is operated, a signal effectively controlled by the electromotive forces induced in another winding 01 said transformer, and biasing means including a condenser and a resistor connected with said signaling circuit between said contacts of said first and second relays and with the grid circuit of said controlled ionization tube to desensitize that tube when said first relay is operated to permit said second relay to be operated only when the train occupies said second track circuit.

10. Railway trafiic controlling apparatus for use either with a first track circuit supplied at times with coded alternating current of a given frequency or with a second track circuit supplied at times with coded direct current of a given polarity comprising, a train, a receiving circuit mounted on the train for receiving energy from such track circuits, a first and a second train carried receiving apparatus; said first receiving apparatus including a high vacuum electron tube, a first relay and a current source; an anode circuit including said first relay and said current source for said tube, a grid circuit for said tube coupled with said receiving circuit to cause operation of said first relay when energy of said given frequency is periodically applied to said grid from said receiving circuit; said second receiving apparatus including a controlled ionization electron tube, a second relay, a condenser and a current source; an anode circuit including said second relay and said last mentioned current source for said controlled ionization tube normally ineffective to ionize the tube, a circuit including said condenser connected with the an-' ode and cathode of the controlled ionization tube to deionize the tube when the tube is conductive, a grid circuit for said controlled ionization tube coupled with the receiving circuit to ionize that tube and operate said second relay when energy of said given polarity is received by said receiving circuit, a filter tuned to resonance at said given frequency interposed in the grid circuit of said high vacuum tube to cause operation of said first relay only when the train occupies said first track circuit, a signaling circuit including a contact of each of said relays effectively controlled when either of said relays is operated, a biasing unit including a condenser and a resistor in multiple interposed in the grid circuit of said controlled ionization tube to establish a normal grid bias for that tube, additional biasing means including another condenser, and a rectifier connected with said biasing unit and with said signaling circuit to modify the grid bias of said controlled ionization tube when said first relay is operated to permit operation of said second relay only when said train occupies said second track circuit.

WILLARD P. PLACE. 

